Pseudo poly amides

Many aliphatic poly(amides), more commonly known as nylons, exhibit an unusual phase transition below their melting point. First noted by Brill [122], the phenomenon has been studied extensively [128-131]. It is observed for instance in nylon (6,6) at a temperature of about 210°C, when the stable low-temperature triclinic oc phase of the crystalline polymer changes to a pseudo-hexagonal phase. 

Pt NMR spectra were employed to study the nature of Pt(bipy)22+ in aqueous alkaline solutions. The data were consistent with formation of a conformationally mobile pseudo-five-coordinate complex involving OH coordination.1079 The time dependence of Pt(II) complexation with poly(amid-oamine)dendrimers was established by 195Pt NMR spectroscopy.1080 The 2H and 13C NMR spectra for solutions of cA-[L2Pt 9-MeAd(-H) ]3(N03)3 show dissociation to a mononuclear species, e.g. cA-[L2Pt 9-MeAd(-H) ]+, where L... 

Applications Poly(Amides) as "Pseudo" PolyfAmino Acids) 214... 

AMIDE-BASED "PSEUDO" POLY(AMINO ACIDS)... 

TABLE 12.2 "Pseudo" Poly(amino acids) Formulated with Amides ... 

Molding and Encapsulating Compounds S ilicone/poly-amide Pseudo-interpenetrating Networks Polysulfone ... 

Pseudo poly(amino acids) in order to improve the properties of poly(amino acids), Kohn and Langer (1986) synthesized polymers where amino acids were not linked through amide bonds but through their side chains. 

Another synthetic concept of polyamides includes the term pseudo-poly(amino acids). In this family of polymers belong naturally occurring amino acids linked by non-amide bonds. Tyrosine, serine and hydroxyproline-derived polymers with ester and iminocarbonate bonds in the chain have been investigated [446],... 

Pulapura and coworkers replaced bisphenol A with derivatives of tyrosine dipeptide resulting in a iminocarbonate-amide copolymer. The iminocarbonate bond was formed between the phenolic hydroxyl group at the tyrosine side chains. These iminocarbonate-amide copolymers can be regarded as pseudo-poly(amino acids) and are being evaluated in biomedical applications. 

Figure 2 (a) The 18/5 right-handed a-helix typical of poly(a,L-peptide)s. (b) The 13/4 right-handed pseudo-a-helix observed in poly(a-alkyl- e,L-aspartate)s. In both helices the hydrogen bond scheme is set between every thi rd amide group but counted at opposite directions with respect to the directionality of the main chain. The larger spheres represent the side chains and hydrogen bonds are indicated as dotted lines. 

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